Force balance controller



r1 |s" INVENTOR.

ROBERT E. OCHS JR April 21, 1959 R. E. OCHS, JR

FORCE BALANCE CONTROLLER Filed July 24, 1956 United States Patent FORCEBALANCE CONTROLLER Robert E. Ochs, Jr., Oreland, Pa., assignor toMinneapolis-Honeywell Regulator Company, Minneapolis, Minn., acorporation of Delaware Application July 24, 1956, Serial No. 599,809

8 Claims. (Cl. 137-82) The general object of the present invention is toprovide a flexible pivot on which a beam may be tilted in response toforces tending to raise one or the other of the beams ends while theremaining beam end is moved downward.

A more specific object of the present invention is to provide theaforementioned flexible pivot with a novel span adjusting means.

A still more specific object of the invention is to provide a spanadjusting means that will apply regulatable amounts of tensile force toa flexible pivot to enable the gradient of the pivot to be changed.

In the desirable form of the invention illustrated by way of example, afirst beam end is subjected to an uprising force by an input diaphragm,an opposite end of the beam is subjected to an uprising force by abellows and a flapper and a flapper nozzle cooperate to automaticallyregulate the pressure applied to the last mentioned end of the beam. Inthe desirable construction shown, the central portion of the beam isrigidly connected to a thin flexible metallic strip which in normaloperation may well be approximately perpendicular to the central portionof the beam.

The lower end of said strip is anchored to a stationary support. Thebeam is supported by the aforementioned thin flexible vertical stripwhich normally tends to maintain said beam in a substantially horizontalposition, and by each end of the beam normally tending to tilt the beamin a direction opposite to the tilting direction impressed on the otherend of the beam.

A better understanding of the present invention may be had from thefollowing detailed description when read in connection with theaccompanying drawing, in which:

Fig. 1 of the drawing shows one type of a force balanced beam structurein which my novel span adjusting leaf spring apparatus may be employed;and

Fig. 2 shows a view taken along line 22 of Fig. 1.

Fig. 1 of the drawing includes a beam 1 shown in an approximatelyhorizontal position, and supported by a thin, normally vertical,metallic strip 2. The beam 1 is shown rigidly connected to a centralportion of the strip 2. The lower end portion 3 of the strip 2 isanchored to the wall formed in a vertical slotted channel 4. The upperend of the vertical strip member 2 is connected to a coil spring 5'which has its upper end connected to a threaded screw element 6. Thelatter 2 extends through and is threadedly supported in a verticalinternal screw threaded stationary supporting element 7. Rotation of thescrew 6 in one direction will cause it to be moved upward and rotationof 6 in the opposite direction will cause it to be moved in a downwarddirection.

This upward or downward movement will cause the lower grooved out flangeportions 8, 9 which are integral with the lower end of the screw 6 toalso be rotated in the same manner. If this rotation is causing thescrew shaft 6 to move in an upward direction the lower flange portion 9will then apply a force in an upward direction to the lower portion ofthe bearing member 11. This upward force will be transmitted through thelower bearing member 11 to the lower surface of the grooved out keyedplate 12. This action Will cause the cylindrical keys 13 and 14 to drivethe plate 12 in an upward direction in the slots 15 and 16 of thestationary member 7. As this latter action occurs it will cause the wireconnections 17 and 18, which are fixedly attached to the underside ofthe plate 12, to apply a force in an upward direction at the connection19 to the upper end of the spring 5.

When the screw 6 is rotated in a direction to make its lower portion 8move in a downward direction it can readily be seen that the bearingmember 21 and the key plate 12 will likewise be moved in a downwarddirection to lessen the tensile force on 17, 18, and spring 5.

It should be noted that since the plate 12 is prevented from turning bythe keys 13 and 14 riding in the slots 15, 16, the aforementionedincrease or decrease in tensile force is applied to the end of thespring 5 in a non-rotatable vertical direction. It can also readily beseen from Fig. 3 of the drawing that the aforementioned lower flangedportion 9 is a ring-shaped plate which is welded at its inner diametralsurface to the lower end of the screw 6 after it has been positioned asshown against its associated bearing member 11.

In Fig. l, the end 22 of the beam 1 is shown connected by a dependingbar 23 to the central portion of an input diaphragm 24. The latter formsa flexible upper wall of a diaphragm chamber 25. This chamber 25 isconnected to a fluid 26 that is representative of the magnitude of avariable control pressure. The opposite end 27 of the beam 1 isconnected to the movable upper end of a bellows element 28. As shown,the lower end 29 of the element 28 is stationary and closed except for abottom wall port 31. The latter is connected by a conduit 32 to avertical, upwardly extending tubular element 33. The tubular element 33has an upper outlet port 34 normally discharging a variable jet of airunder pressure against the underside of an approximately hori zontalflapper element 35. The latter has one end connected to and extendinghorizontally away from the adjacent end of the beam 1. The member 33 hasa restricted lower end portion 36 receiving air 37 under pressure froman air supply conduit 38. Also connected to this tubular element 33 is atransmitting conduit 39. This conduit is used to transmit to a remotelylocated receiving instrument, e. g., a pressure indicating orcontrolling apparatus, any changes in pressure that take place in thischamber due to the displacement of the flapper 35.

In the normal operation of the apparatus shown in the drawing, anincrease in the input pressure 26 transmitted to the diaphragm chambercauses the beam 1 to tilt in the direction to raise the left end 22 ofthe beam 1 while lowering the opposite beam end 27. The variablepressure transmitted to or away from the bellows 28 through the opening31 in the normally stationary bottom wall 29 of the element 28 by theconduit 32, increases or diminishes as the flapper 35 is moved towardand away from the nozzle 34.

In the contemplated normal operation of the apparatus illustrated, anincrease or decrease in the pressure acting on the underside of thediaphragm 24 results in an up or down movement of the beam end 22. Asthe diaphragm 24 moves the beam end 22 up or down, the beam end 27 tendsto compress the bellows 28, or permits the latter to expand, with theresult that the flapper 35 tends to move respectively toward or awayfrom the nozzle 34. When the flapper 35 moves downward toward the nozzle34, the pressure in the tubular element 33 increases as does thepressure in the bellows 28. The pressure increase in the bellows 28tends to raise the beam end 27 and to lower the beam end 22 and therebydecrease the pressure impressed on the flapper member 35 by the element33. In practice the increase in pressure then acting upward on thediaphragm 24, is neutralized in part by the increase in the pressure inthe nozzle element 33.

In general, any increase in the input pressure impressed on thediaphragm 24 causes the beam end 22 to move and increase the pressure innozzle element 34. In this way the input pressure 26 causes the flappervalve and bellows to transmit to the beam 1 a feedback force that actsto return the beam to a balanced position. The spring gradient of thestrip 2 plus the aforementioned balancing force thus acts to balance outthe input force impressed on the beam 1 by the magnitude of the controlpressure 26. When the coil spring 5 is adjusted in an upward directionby rotating 6 in support 7 the coil spring 5 will be caused to carry alarger tensile load and the gradient of leaf spring 2 will be increased.When such an upward adjustment of spring 5 takes place it can thus beseen that a larger input pressure 26 acting on the diaphragm 24 andmember 23 will be required to deflect the beam to the same extent asbefore; thus, the span is increased through the use of the tensile forceapplied to the upper end of a variable gradient strip 2. Likewise, whenthe tensile force on the coil spring 5 is reduced by rotating the screwelement in a downward direction it will be readily apparent from theaforementioned remarks that the gradient of the strip 2 will be reducedand the beam will thus require a much smaller pressure 26 to deflect itto the same extent as before. One of the significant benefits derivedfrom the span adjusting technique disclosed in this application is thatsuch an adjustment may be accomplished without incurring any undesirablechange in the zero position o the instrument.

A change in the tensile force thus causes a change in the momentrequired to cause a predetermined angular deflection of the beam. Inother words, the change in the tensile force and the resultant gradientchange thus causes a change in the deflection of the leaf spring 2.

As will be apparent, however, the apparatus shown is characterized byits inherent simplicity and effectiveness. While each end of the beam 1must move both horizontally and vertically, the required movements maybe so small as to be practically insignificant in magnitude.

The present invention provides a novel span adjusting means that altersthe tensile force and the gradient of a strip member that pivotallysupports a beam. Furthermore, the adjustment of the span adjusting meansenables the operator to increase or decrease the magnitude of thefeedback force that must be overcome by an input force applied to thebeam in order that a predeterminedtilt of the beam may be effected bysuch an input force.

What is claimed is:

1. A beam pivoted to oscillate about an intermediate portion of the beamlength, said beam being comprised of a pivot of a leaf springconfiguration with an end fixedly attached to a first stationary memberand its opposite end fixedly connected by means of a resilient member toa second stationary member, means engaging a portion of said beam at oneside of the said intermediate beam portion, means engaging a second beamportion at the opposite side of said intermediate beam portion, saidbeam portions being transverse to the beam length and each connected toa separate flexible chamber and each having an inlet for the inflow offluid into its associated chamber, a flapper element connected to andextend ing away from the second beam portion, and means for passingpressure fluid into one end of a conduit adjacent said flapper elementand for passing pressure fluid out of said conduit into engagement withsaid flapper element and into said chamber that is adjacent said secondbeam end.

2. A beam as specified in claim 1 and including a mechanically adjustedmeans for varying the tensile force that said resilient means can applyto said opposite end portion of said leaf spring.

3. A beam as specified in claim 2 wherein said mechanical adjusted meansis comprised of a threaded connection between said second stationarymember and said resilient means.

4. A beam pivoted to oscillate about a deflectable leaf springpositioned intermediate the beam ends, means acting on one end of saidbeam in a direction tending to tilt the beam in a direction transverseto the length of the beam, means acting on the second end of said beamin a direction tending to tilt said beam in a direction approximatelyparallel to the first mentioned direction, a flapper element connectedto and extending away from the second end of said beam and in thegeneral direction of the beam length, a stationary means for discharginga fluid jet against one side of said flapper element, means for varyingthe distance between said stationary means and the adjacent side of saidbeam including said means acting on one end of said beam and means forvarying the pressure impressed on said beam including said second meansacting on the second end of the beam.

5. A beam pivoted to oscillate about a portion of said beam intermediatethe ends of said beam, said bean being comprised of a pivot of a leafspring configuration with one end fixedly attached to a stationarymember, an intermediate portion attached to said beam and a remainingend mounted by means of an adjustable spring tensioning means to astationary member, means acting on one end portion of said beam tendingto tilt said end portion in one direction and means acting on theopposite end portion of said beam tending to tilt the latter in adirection opposite to: the first mentioned direction, a flapperextending away from an adjacent end of said beam, a conduit transverseto said flapper and having an outlet end adjacent and transverse to theend of the flapper, and means for continuously passing fluid into saidconduit and thence out of the outlet end of the conduit and intoengagement with said flapper.

6. A substantially horizontal beam, a flexible vertical elementextending through and being attached to a central portion of said beam,a stationary member in which the lower end of said element is fixedlyattached, an adjustable resilient means connected to the upper portionof said flexible element and being operably connected to apply a tensileforce to said element and control elements supported by elementssuspended on each of the end portions of said beam and subjecting saidbeam ends to vertical forces adapted to longitudinally tilt said beamabout said flexible element.

7. A means for adjusting the span of a force balance apparatuscomprising, an elongated leaf spring, a beam pivoted in a see-sawfashion on a central portion of said leaf spring pivot, said pivothaving one of its elongated ends fixedly connected to a stationarymember and its opposite end adjustably mounted in a tensile forcegenerating means and a mechanically actuated means operably connected tosaid force generating means for causing said generating means to changethe magnitude of the tensile force that it is applying to the said endof said leaf spring.

8. A span adjusting apparatus for use in a force balance systemcomprising, a cantilever leaf spring fixedly attached at its lower endto a stationary member and protruding upwardly from said member, ahorizontally positioned beam pivoted to a portion of said leaf spring, afluid pressure flapper-nozzle apparatus positioned relative to said beamto be adjusted thereby, a first pressure responsive means connected tosaid beam and to the nozzle of said flapper-nozzle apparatus to apply aforce to said beam in accordance with the back pressure of said nozzle,a force producing means connected to said beam to provide an input forcethereto for altering the amount of fluid bled from said flapper-nozzleapparatus, said force producing means comprising a pressure responsivediaphragm means coupled to said beam and an adjustable resilient meansconnected at its lower end to the upper end of said leaf spring foraltering the amount of tensile force that is applied to the leaf spring.

No references cited.

